The present invention relates to the collecting of products secreted by trees and refers more particularly to improving the harvesting of pins resin, or oleoresin, produced by coniferous trees (for example: pinus pinaster, pinus eliattii, pinus sylvestris, pinus nigra, pinus pinea, pinus palustris, pinus edulis, pinus canariensis, pinus merkusii, pinus kashya, etc.), when their bark is cut sufficiently deeply to reach the surface of the wood.
The outflow of such products enables the tree to protect itself against its natural enemies (insects, fungi, etc.) by producing a layer of oleoresin which dries in air by the evaporation of the volatile part which it contains, thereby forming a crust which will enable the bark to grow back again A region forms around the incision that is very rich in channels that secrete this oleoresin, especially from the top of the incision, since the outflow follows gravity.
The constituents of the oleoresin, monoterpenes and resinic acids, are of very great industrial importance in many different flourishing sectors, such as the synthesis of raw materials for perfumes, inks, adhesives and so forth.
The object of the invention is to provide a method of collecting the resin in such a way that these products can be obtained at a price that will compete with raw materials produced from petroleum without diminishing the quality of the wood of the trees.
By contrast, currently used methods harvest only some of the outflow, partly by allowing the secretory channels to become blocked and partly by allowing the volatile products, whose industrial value is very considerable, to evaporate into the air. Furthermore, the systems generally employ placing metal parts into the wood, the presence of such parts is undesirable for the wood conversion industry.
In patents FR 691,361, FR 725,773 and FR 725,774, a method is described for tapping secretions using a manual mechanical apparatus enabling the tree to be prepared in order for a xe2x80x9cclosedxe2x80x9d oleoresin tapping system to be placed against it.
Patent FR 2,746,582 discloses a closed-vessel tapping system applied to the technique of traditional hand resin-tapping and film distillation of the oleoresin on the harvesting site, in a specially equipped vehicle.
Patents U.S. Pat. No. 3,959,925 and U.S. Pat. No. 4,291,492 disclose tractors possessing complex mechanized jointed-arm systems for making incisions in the bark of trees and applying an activator, but according to A. W. Hodges and W. D. Shoup (Naval Stores Review, 1988, July/August, pp. 13-19), their profitability is low, being directly connected to the firmness and flatness of the ground and their cost is high.
Many patents disclose systems for activating the secretion of the oleoresin, generally employing sulphuric acid, as noted by Prof. G. Stephan in Naval Stores Review, 1990, November/December, p. 13. To take one example, patent FR 2,160,742 discloses a solution containing sulphuric acid and a lignosulphonate.
The object of the invention is to devise a collecting method that will make it possible to bring about the greatest possible outflow of product from the secretory channels of the tree.
It is also an object of the invention to devise a collecting method that makes it possible to limit the work on the tree, enabling each person to operate on the greatest possible number of trees per unit time, during the preparation of the tree by making an incision in the bark and for harvesting the product, while avoiding the current practice of removing bark at the start of the season and harvesting the barras resin at the end of the season.
It is also an object of the invention to devise a method of collecting the greatest possible amount of expressed oleoresin in as pure a state as possible in order to obviate the need for subsequent processing, the cost of which is prohibitive.
For this purpose the resin must be protected, as it emerges from the surface of the tree, from rubbish (bits of bark, branches, insects, etc.) and from rainwater which would carry away the tannins present in pine bark.
Similarly, the method of the invention seeks to limit the evaporative losses of the essences (terpenes) whose volatility is sufficient to greatly reduce the yield of the harvest. The method of the invention seeks furthermore to make it possible to obtain a high-quality product with limited oxidation of the oleoresin in the presence of air, water and ultraviolet light emitted by the sun.
The subject of the invention is therefore a method of collecting products secreted by trees, particularly for pine resin or oleoresin produced by coniferous trees, the method comprising the following steps: making an incision in the tree trunk of sufficient depth to reach the surface of the wood; applying to the incision a product to activate the outflow of the product to be tapped; placing in the incision a receptacle of corresponding shape, in the lower outer part of which is an outflow tube; characterized in that it also consists in fixing to the outflow tube of the receptacle a collecting bag made of a plastic that is resistant to the product collected; removing the bag when filled with product and closing it; storing the closed bags in a container and closing the container when filled with bags; transporting the closed container to a product recovery site; treating the bags contained in a container in order to clean their exterior soiled in the course of the product collecting operation; opening the cleaned bags; and recovering the product which they contain.
The invention also relates to a product collecting bag for carrying out the method according to the technique defined above, characterized in that it comprises a fixing means that fits the shape of the end of the outflow tube of the receptacle.
The invention also relates to an apparatus for making incisions in the trunk of a tree for carrying out the collecting method according to the technique defined above, characterized in that it comprises a frame with means for fixing it temporarily to the bark of the trunk and manual means for holding the frame fixed to the trunk, a rotary cutting tool that can be displaced at least axially on the frame and, mounted on the frame, a drive motor for rotating the cutting tool.